Podcast
Questions and Answers
Which process primarily contributes to the formation of a caldera?
Which process primarily contributes to the formation of a caldera?
- The emptying of the magma chamber beneath the volcano during a large eruption that causes the crater wall to collapse. (correct)
- Continuous ejection of lava fragments leading to a steep-sided cone.
- Stream-driven explosions resulting from contact between hot rocks and water.
- Gradual accumulation of lava flows over extended periods.
How do phreatic eruptions differ from phreatomagmatic eruptions?
How do phreatic eruptions differ from phreatomagmatic eruptions?
- Phreatic eruptions involve magma, whereas phreatomagmatic eruptions do not.
- Phreatic eruptions are characterized by violent explosions, whereas phreatomagmatic eruptions are not.
- Phreatic eruptions produce fine ash explosions, whereas phreatomagmatic eruptions do not.
- Phreatic eruptions are stream-driven, caused by hot rocks contacting water, whereas phreatomagmatic eruptions are caused by water interacting with magma. (correct)
Which type of volcano is most likely to have alternating layers of lava and pyroclastic deposits?
Which type of volcano is most likely to have alternating layers of lava and pyroclastic deposits?
- Shield volcano
- Composite volcano (correct)
- Lava dome
- Cinder cone volcano
If a volcano has not erupted in recorded history, but shows no signs of activity, how would it be classified?
If a volcano has not erupted in recorded history, but shows no signs of activity, how would it be classified?
What is the primary difference between magma and lava?
What is the primary difference between magma and lava?
Which volcanic eruption type is characterized by excessively explosive eruptions of gas and pyroclastics?
Which volcanic eruption type is characterized by excessively explosive eruptions of gas and pyroclastics?
Why are volcanoes considered vital for sustaining life on Earth?
Why are volcanoes considered vital for sustaining life on Earth?
What is the main characteristic of a shield volcano that distinguishes it from other types of volcanoes?
What is the main characteristic of a shield volcano that distinguishes it from other types of volcanoes?
Flashcards
Volcano
Volcano
An opening in the Earth's surface where molten rock, gases, and ash erupt.
Crater
Crater
A funnel-shaped depression at the top of a volcano formed by eruptions.
Caldera
Caldera
A volcanic crater formed when part of the crater wall collapses after an eruption.
Magma
Magma
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Lava
Lava
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Shield Volcano
Shield Volcano
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Cinder Cone Volcano
Cinder Cone Volcano
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Plinian Eruption
Plinian Eruption
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Study Notes
Volcano Definition
- Volcanoes are openings in the Earth's surface where molten rock, smoke, gases, and ash are ejected.
Volcano Parts
- Base: The bottom of the volcano.
- Slope: The sides of the volcano.
- Summit: The top of the volcano, where the crater is located.
Crater
- A funnel-shaped depression at the top of a volcano formed by explosive eruptions.
- The mouth or opening of the volcano.
Caldera
- A volcanic crater formed when part of the crater wall collapses after an explosive eruption.
- Usually triggered by the emptying of the magma chamber beneath the volcano during a large eruption.
Magma vs Lava
- Magma: Hot, fluid or semi-fluid material below or within the Earth's crust, usually made of molten rock.
- Lava: Magma that has been ejected out of a volcano. Lava is an Italian word meaning "to slide," reflecting how molten rock moves on the surface.
Types of Volcanoes by Shape
Shield Volcano
- Formed by the accumulation of lava that flows freely from the volcano.
- Non-viscous lava creates a broad, slightly domed structure resembling a warrior's shield.
- Example: Mauna Loa in Hawaii.
Cinder Cone Volcano
- Built from ejected lava fragments.
- Characterized by steep slopes and a wide crater.
- Also known as scoria cones.
- Example: Mount Paricutin in Mexico.
Composite Volcano
- Also known as stratovolcanoes.
- Large, nearly perfect cone-shaped structures formed by layers of solidified lava and pyroclastic deposits (fragments of volcanic rock).
- Some of the Earth's grandest mountains.
- Example: Mayon Volcano in the Philippines.
Types of Volcanoes by Eruption
Phreatic Eruption
- Stream-driven eruption caused by the contact of hot rocks with water.
- Also known as hydrothermal eruptions.
- Example: Taal Volcano eruption in January 2020.
Phreatomagmatic Eruption
- Violent eruption caused by the interaction of water and magma, resulting in fine ash explosions.
- Different from phreatic eruptions, where only hot rocks contact water.
Strombolian Eruption
- Characterized by periodic weak to violent eruptions with fountaining lava.
Vulcanian Eruption
- Characterized by tall eruptions that reach up to 20 kilometers high, accompanied by pyroclastic flows and ash tephra.
Plinian Eruption
- Excessively explosive eruption of gas and pyroclastics.
- Intensely violent eruption.
- Example: Mount Pinatubo eruption in 1991.
Volcano Activity
- Active Volcano: A volcano with a recorded history of eruption.
- Inactive Volcano: A volcano with no recorded history of eruption and no current activity. Example: Mount Kanlaon in the Philippines.
Volcanic Importance
- Volcanoes play a vital role in sustaining life on Earth.
- They contribute to Earth's warmth and water cycle, essential for life.
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